The present invention applies to the art of securing insulation to the walls of furnaces, kilns, soaking pits and the like and, more particularly, to securing compressible insulation blankets to the inner walls of such apparatus.
Several years ago the predominant method of insulating such heating apparatus as kilns, soaking pits, process heaters, car bottom furnaces and incinerators and other devices of that nature was to use the heretofore conventional and well known firebrick. The process of bricking the heated areas was expensive from a labor standpoint and extremely time-consuming. Additionally, replacement of the brick lining in the heating devices was both expensive and time-consuming.
More recent developments in the art of insulating kilns and like devices is the utilization of insulation blankets. The insulating blankets are made of varying compositions usually interwoven fibers which contain a high consistency of alumina. The blankets come in varying thicknesses from one to three inches and are formed into rolls of varying widths.
During the insulating process, the blankets are applied to the walls of the kiln or like device in layers of anywhere from one to three layers and often in a crisscross pattern. The blankets may be secured to the walls of the kiln or like device in a number of different ways.
In nearly all of the heating devices such as kilns and the like, the wall to which the blankets are supported is a metallic wall known as the cold wall. One manner of securing the blankets is the utilization of a threaded fastener which employs a drill point and self tapping combination on the end of the fastener. The fastener is drilled and threaded into the wall and projects outwardly from the wall. A number of these fasteners are spaced along the wall and blankets impaled upon the fasteners. Thereafter, a washer and nut are applied to the threaded fastener to pull the blanket down into secured position.
Another device which is used for smaller blankets is a pin which has a large washer secured on the end of the pin. The pin is pushed through the blanket and against the metal cold wall and stud welded in place to secure the blanket.
A third device in prevalent use is a stud and washer combination wherein the stud includes a plurality of tapered notches. The studs are welded to the cold wall in a given array or fashion and the blanket impaled upon the studs. Thereafter, the washers which have a complementary aperture therein are placed over the stud to compress the blanket and rotated 90.degree. and released whereupon the blanket brings the washer into locking engagement with the stud.
The self tapping threaded fastener type device is both expensive and time-consuming in installation. The pin with the large washer affixed to the end of the pin does not have sufficient holding capabilities for heavier blankets. The stud with the tapered notches and washer combination, while an effective means for securing the insulation blanket, is an expensive combination given the rising costs of stainless steel material of which the combination is manufactured as well as the manufacturing technique involved.
What is required by the industry as a suitable insulation hanger for insulating blanket is an inexpensive hanger both from the standpoint of manufacture and installation as well as one which has a positive lock against unsecuring of the hanger once in place.